From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=36659 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Oxe0L-0006iW-7G for qemu-devel@nongnu.org; Mon, 20 Sep 2010 06:53:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Oxe0J-0003c8-T6 for qemu-devel@nongnu.org; Mon, 20 Sep 2010 06:53:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53889) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Oxe0J-0003bR-Mo for qemu-devel@nongnu.org; Mon, 20 Sep 2010 06:53:47 -0400 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o8KArhm9030393 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 20 Sep 2010 06:53:44 -0400 Date: Mon, 20 Sep 2010 11:53:41 +0100 From: "Daniel P. Berrange" Subject: Re: [Qemu-devel] Re: [PATCH] Make NIC model fallback to default when specified model is not supported Message-ID: <20100920105341.GD18143@redhat.com> References: <4C972DCF.1050003@redhat.com> <4C9738B4.4010809@redhat.com> <4C973C12.7050905@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C973C12.7050905@redhat.com> Reply-To: "Daniel P. Berrange" List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michal Novotny Cc: Paolo Bonzini , qemu-devel On Mon, Sep 20, 2010 at 12:48:50PM +0200, Michal Novotny wrote: > On 09/20/2010 12:34 PM, Paolo Bonzini wrote: > >On 09/20/2010 11:47 AM, Michal Novotny wrote: > >>Hi, > >> > >>this is the patch to introduce a NIC model fallback to default when > >>model > >>specified is not supported. It's been tested on i386-softmmu target on > >>i386 host using the Windows XP x86 virtual machine and by trying to > >>setup > >>the invalid (unsupported) model of NIC device. Also, the new constant in > >>the net.h called the DEFAULT_NIC_MODEL has been introduced to be able to > >>change the default NIC model easily. This variable is being used to set > >>the default NIC model when necessary. > > > >Why? If it's not supported, it shouldn't run. > > > >Paolo > > I don't think so. It makes sense it shouldn't run for case of pure qemu > but since there's newly added support for xen (and also there's support > for other virtualization platforms to be used with the qemu device > model) it should fallback with just a warning since otherwise those > platforms, like e.g. mentioned Xen, will leave defunct device models > there and the guests won't run be running at all ending up with no > state. If there's a warning with information it's falling back to > default the user can notice if he wants to but it won't leave the > defunct device models anymore which can be pretty hard to determine > what's going on there for standard user that doesn't have much > experience with e.g. Xen yet. IMHO this is just a bug in the xen mgmt layer. If the QEMU device model dies/quits, then XenD should teardown the guest, since you can't do any useful work once the device model has crashed. Silently switching to a different NIC model than the one requested is definitely a wrong approach. Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://deltacloud.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|